Error cases in AddressUpgradeable.sol::verifyCallResultFromTarget

Den · June 29, 2023, 5:14pm

OpenZeppelin/openzeppelin-contracts-upgradeable/blob/bc95521e34dcd49792065e264a7ad2b5a86f0091/contracts/utils/AddressUpgradeable.sol#L204


      
           */
          function verifyCallResultFromTarget(
              address target,
              bool success,
              bytes memory returndata,
              string memory errorMessage
          ) internal view returns (bytes memory) {
              if (success) {
                  if (returndata.length == 0) {
                      // only check isContract if the call was successful and the return data is empty
                      // otherwise we already know that it was a contract
                      require(isContract(target), "Address: call to non-contract");
                  }
                  return returndata;
              } else {
                  _revert(returndata, errorMessage);
              }
          }
          
          /**
           * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the

In Address.sol, what does the text mean? Why not requring isContract at start of the function?

barakman · June 29, 2023, 5:31pm

The description is very clear, so I doubt that I can explain it any better than it already is, but I'll try:

If a function-call on some address has succeeded but the length of the data returned from that function is zero, then this address is possibly NOT the address of a contract, hence we need to ensure that there is indeed a contract deployed at this address.

If a function-call on some address has succeeded and the length of the data returned from that function is larger than zero, then this address is definitely the address of a contract, hence we do not need to ensure that there is a contract deployed at this address.

Den · June 29, 2023, 8:44pm

Super!
sometimes, it's hard to grasp the meaning from short comments

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Error cases in AddressUpgradeable.sol::verifyCallResultFromTarget

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